The Heavy Weights: Measuring Higgs and Top-Quark Associated Production at the ATLAS LHC Experiment to Probe Beyond the Standard Model

DOMAIN: Particle and Astroparticle Physics and associated scientific domains

SUPERVISOR: Ricardo Gonçalo

CO-SUPERVISOR: Yvonne Peters

HOST INSTITUTION: Laboratório de Instrumentação e Física Experimental de Partículas

DEGREE INSTITUTION: Universidade de Coimbra

ABROAD-INSTITUTION: University of Manchester

ABSTRACT

After an intense search, the associated production of the Higgs boson with a top quark pair was finally observed in 2018. This production channel provides the best way to directly measure the coupling between Higgs and top, the heaviest fundamental particles in the Standard Model (SM). But it also provides a way to look beyond the SM, in particular to search for signs of a non-standard Higgs boson, leading to CP-violation in the Higgs sector. Such a component is well justified in scenarios like the two-Higgs doublet model, and finding it would constitute a major discovery. In particular, it could lead to understanding why there is a huge asymmetry between matter and antimatter in the Universe. In this leading edge research, the selected student will analyze data collected by the ATLAS experiment during the LHC Run 3, to start in 2021. He or she will have the opportunity to participate in the operation of the experiment at CERN. The student will integrate the Portuguese ATLAS team and will use recent techniques developed in our group to enhance the experimental sensitivity of the analysis. He or she will be co-supervised by a colleague from the University of Manchester, where the student will spend part of the time of the PhD, as foreseen in the grant. Besides the Manchester group, the student would work in a vibrant international team within the ATLAS collaboration.